Hydrodynamic behavior of a new wave energy convertor: The Blow-Jet

• A novel WEC device, named Blow-Jet, is proposed.
• Efficiency and wave-induced pressure distribution were studied in a wave flume.
• 3D OpenFOAM model adequately reproduced the hydrodynamics inside the Blow-Jet.
• Optimal design configuration was found in terms of device submergence and tilting.

The work presented here focuses on evaluating the interaction between ocean waves and a device designed to harness their energy. The device, called Blow-Jet, consists of a narrowing structure that concentrates waves and transforms their energy from potential and kinetic to kinetic, turning the oscillatory flow into an intermittent jet that can be easily guided to an impulse turbine. The new device is designed to feed low energy demands such as secondary fuel generators (e.g. hydrogen production). Several experimental tests were carried out to investigate the hydraulic behavior of the Blow-Jet. Results indicate that even for low energetic wave trains, the device is able to capture energy and amplify the water velocity, which is indeed energy conversion capacity. In order to evaluate the flow field inside the device, a high resolution 3D numerical model OpenFOAM is utilized. Good agreement was found between the pressures exerted to the walls of the device with that computed with the numerical tool. The combination of numerical and experimental results confirmed the optimal geometry, location and position of the Blow-Jet, while the need for some geometric changes was detected after the analysis of numerical model results. The Blow-Jet has shown itself to be a potential WEC with acceptable efficiency.